Pulse sensor question

Harley

This is a totally new area for me. I'd like to display one's pulse. Personal use only.

1. Does anyone know of an efficient design to sense a pulse/heart beat? The sensor output probably needs to be amplified, possibly filtered, but is there anything else to consider in processing the signal? Does such a sensor exist ready to purchase?

2. Would sigma-delta a/d scheme work with such an amplified signal, as it is a fairly low frequency (assuming 300 beats/min at max.)? High accuracy is not required; only to view the waeform when suspected abnormal pulse is occuring. A LCD module is planned for the 'display'.

Thank your for any suggestions.

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Harley Shanko

Bob Lawrence (VE1RLL)

Try this: A Simple Heart Rhythm Monitor Utilizing the Parallax Propeller Microcontroller

rayslogic.com/Propeller/Programming/PropEKG/PropEKG.htm

HollyMinkowski

Sending IR light from an IR LED through the skin and detecting it with an opto transistor will yield
pulses because as the blood rushes through it reduces the amount of IR passing through the tissue.

a google search for - pulse IR LED infra red - will probably turn up multiple sets of plans for such a
device.

Those little pulse/O2 monitors that you stick your finger in to use operate in this fashion.
Not certain how they discern the O2 level from the IR data though?

No chance of shock from such a device as no actual circuit contact with the body.

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- Some mornings I wake up cranky.....but usually I just let him sleep in -

Leon

Oximeters use two LEDs - red and IR - and measure the relative absorption of the light which changes with blood oxygen levels.

Leon

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Amateur radio callsign: G1HSM
Suzuki SV1000S motorcycle

Harley

Wow! Such quick info.

Thank you Bob, Holly, and Leon for the level of info. I've had my head too close to the grindstone to have caught that info from 'rayslogic.com'. That is a huge start on what's involved. I was just mulling over the idea and decided to ask my questions months before being able to move on to another project. Much appreciated.

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Harley Shanko

Agent420

You might consider adding EKG capability as well ;-)

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